Wall thickness and the presence of defects such as cracks are important factors in determining the fitness-for-service of structures such as above and below ground pipes and tanks. When a pipe is in operation, it can be subject to corrosion and/or erosion due to the content, flow and/or environmental conditions inside or outside of the pipe. Cracks can form and propagate due to the presence of manufacturing defects, creep, thermal cycling, fatigue and environmental conditions resulting in high temperature hydrogen attack (HTHA) stress corrosion cracking, etc. Corrosion and/or erosion results in the reduction in wall thickness, which can reach a point at which operating conditions becomes unsafe, considering that the pipe can be pressurized and may contain hazardous or flammable materials. Likewise formation and propagation of cracks can cause similar unsafe conditions. A failure may cause catastrophic consequences such as loss of life and environmental damage in addition to the loss of the use of the asset, and any corresponding costs associated with repair, loss of capacity and revenue loss.
Ultrasonic non-destructive evaluation techniques are commonly used for evaluating the integrity of industrial components. In the case of measuring wall thickness reduction due to erosion/corrosion, the traditional process involves using a portable handheld instrument and ultrasonic transducer (probe) to measure the wall thickness. The instrument excites the probe via an electrical pulse, and the probe, in turn, generates an ultrasonic pulse which is transmitted through the structure. The probe also receives an echo of the ultrasonic pulse from the structure, and converts the pulse back into an electrical signal. The ultrasonic pulses that are transmitted into and received from a structure are used to determine the relative position of the surfaces (i.e. thickness) of the structure wall. More specifically, by knowing the travel time of the ultrasonic pulse from the outer wall to the inner wall and back (ΔT) and acoustic velocity (V) of the ultrasonic pulse through the material of the structure (through calibration or just initialization), a wall thickness (d) can be calculated—i.e. d=ΔT*V/2. In a similar fashion, ultrasound can be used to detect the presence of defects such as cracks in bulk material or in welds. Here, the gauge is set up to look for the presence of ultrasonic echoes returning from the defect. The presence of an echo in a particular area of interest would indicate the presence of a flaw. There are many variants of these two basic descriptions of ultrasonic thickness gauging and flaw detection that are known to skilled practitioners of ultrasonic nondestructive evaluation. These approaches require an operator to manually position a probe on the wall of the asset to take a reading. Not only does this necessitate the operator manually taking each reading, but also the measurement location must be accessible, which can be challenging and costly. For example buried pipelines require excavation to access, insulated pipe requires costly removal of the insulation, offshore assets require helicopter or boat access, and elevated vessels may require scaffolding or crane access. While the measurement is relatively simple, the cost of access (scaffolding, excavation, insulation removal, etc) is often much higher than the cost of measurement. Moreover, the operator may be subjected to hazardous conditions while taking the readings.
Another problem with the traditional approach is that the data is captured on a proprietary device, making the distribution and further processing of the data inconvenient and potentially subject to translation errors if the data is recorded manually. That is, once the data is acquired by the handheld device, the device usually needs to be connected to a computer running a proprietary software to download, analyze and report the data. Often times the software is only licensed to a single computer so multiple software licenses are required. Furthermore, the technology requirements for the software installations can be challenging and maintenance can be problematic—e.g., computer replacement, operating system upgrades, etc. Additionally, inspection reports are then written and often shared with the operator or asset owner via emailed or paper reports, but not via cloud based data access.
Furthermore, to obtain trending data with thickness resolution of 0.001″ or better requires that the transducer be placed in the same exact location for consistent readings at regular time intervals. This is difficult and often impractical especially when the data-capture rate needs to be frequent. Variations in operator and/or equipment tend to skew the quality and integrity of the measurement data.
One approach for avoiding some of the aforementioned problems is to use installed sensors/systems for asset-condition or -integrity measurement. The sensors are permanently or semi-permanently installed on the asset and can be covered with soil, insulation and/or can be wired to a convenient place for easy user access. This also overcomes the limitation in manual thickness measuring that it is never possible to place the sensor in the same position for subsequent readings resulting in inherent measurement error Automated systems require no operator to be in the vicinity of the asset and can stream data to a control room or to an operator's desk.
Current permanently- or semi-permanently installed systems tend to suffer, however, from a number of shortcomings. For example, some of the systems require point-to-point connections between the user interface and the sensors. This becomes problematic as the number of sensors on a structure increases, requiring bundles of wire to be run to the interface. Additionally, conventional systems tend to require proprietary user interfaces to receive signals from the sensors and to apply proprietary algorithms to convert these signals to usable data. Thus, the user is forced to interface or download information from these proprietary controllers to a PC/tablet or other user device. Still other conventional systems use wireless signals between the sensor and the controller. Again, these links tend to be proprietary and require a proprietary controller to receive and process the data from the sensors. Such systems are also inappropriate for underground use. Further, wireless transmissions tend to be slower and thus latency in the system can be an issue. Yet another problem of the conventional system is analog signals between the sensors and the controller. As is known, analogs signals are more susceptible to corruption and degradation, and thus misinterpretation, especially as the distance between the sensor and the controller increases.
Therefore, Applicants recognize a need for a system that is modular and facilitates non-proprietary transmission of digital signals using off-the-shelf user interfaces. The present invention fulfills this need among others.